（一）微服务（垂直API）

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项目地址

• 教程作者：
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• 代码仓库地址：

• 所用到的框架和插件：

dbt 
airflow

一、创建第一个垂直API

1.1 创建Common层

1. ICommand接口

1. ICommand.cs

using MediatR;
namespace BuildingBlocks.CQRS;
public interface ICommand : ICommand<Unit>; 
public interface ICommand<out TResponse> : IRequest<TResponse>;

2. ICommandHandler.cs

using MediatR;
namespace BuildingBlocks.CQRS;
public interface ICommandHandler<in TCommand>  //无返回值: ICommandHandler<TCommand, Unit>where TCommand : ICommand<Unit>;public interface ICommandHandler<in TCommand, TResponse> //有返回值: IRequestHandler<TCommand, TResponse>where TCommand : ICommand<TResponse>where TResponse : notnull;

in(Contravariant)：只在参数中使用的泛型类型

2. IQuery接口

1. IQuery.cs

using MediatR;
namespace BuildingBlocks.CQRS;
public interface IQuery<out TResponse> : IRequest<TResponse>  where TResponse : notnull;

2. IQueryHandler:

namespace BuildingBlocks.CQRS;
public interface IQueryHandler<in TQuery, TResponse>: IRequestHandler<TQuery, TResponse>where TQuery : IQuery<TResponse>where TResponse : notnull;

1.2 创建API

1. 实体

namespace Catalog.API.Models;
public class Product
{public Guid Id { get; set; }public string Name { get; set; } = default!;public List<string> Category { get; set; } = new();public string Description { get; set; } = default!;public string ImageFile { get; set; } = default!;public decimal Price { get; set; }
}

2. Handler

namespace Catalog.API.Products.CreateProduct;
public record CreateProductCommand(string Name, List<string> Category, string Description, string ImageFile, decimal Price): ICommand<CreateProductResult>;
public record CreateProductResult(Guid Id);internal class CreateProductCommandHandler : ICommandHandler<CreateProductCommand, CreateProductResult>
{public async Task<CreateProductResult> Handle(CreateProductCommand command, CancellationToken cancellationToken){var product = new Product{Name = command.Name,Category = command.Category,Description = command.Description,ImageFile = command.ImageFile,Price = command.Price};return new CreateProductResult(Guid.NewGuid());        }
}

3. endpoint

namespace Catalog.API.Products.CreateProduct;
public record CreateProductRequest(string Name, List<string> Category, string Description, string ImageFile, decimal Price);
public record CreateProductResponse(Guid Id);
public class CreateProductEndpoint : ICarterModule
{public void AddRoutes(IEndpointRouteBuilder app){app.MapPost("/products",async (CreateProductRequest request, ISender sender) =>{var command = request.Adapt<CreateProductCommand>();var result = await sender.Send(command);var response = result.Adapt<CreateProductResponse>();return Results.Created($"/products/{response.Id}", response);}).WithName("CreateProduct").Produces<CreateProductResponse>(StatusCodes.Status201Created).ProducesProblem(StatusCodes.Status400BadRequest).WithSummary("Create Product").WithDescription("Create Product");}
}

1.3 使用Marten作为ORM

• Marten只能用于postgresql的ORM使用